The Contractor shall attemt to define techniques for the isolation in high yields and purity of viable, functional lymphocytes, and cryopreservation of such lymphocyte populations with the emphasis on recovery of the cell population with high yields of cells with reteition of their functional capability. Assays for recovery of structural integrity shall include: Total cell count and differential; Trypan blue viablitiy; Stability of 51Cr binding to lymphocytes; Rosette formation (E and EAC); Fluorescent anti-immunoglobulin staining (B cells); and Monocyte quantitation by FC receptor assay. Function shall be assayed in vitro in the following assays: Lymphocyte transformation by mitogen, soluble and cell associated antigen, and, if possible, by tumor associated antigen; Direct 51Cr cytotoxicity; Stimulated 51Cr cytotoxicity; and Monocyte function by hexose monophosphate shunt activity stimulated by phagocytosis.